It's all in System Restore and Volume Shadow Copy, mostly the former
I'd guess.

So, there are no shadow copies to clean up and there is only one backup point
on my computer.

Where do I look now?  Any ideas?

Hi, rayhorn13.

Sorry to come late to this old thread, but I just now spotted it.  You
probably have found your answer by now (or given up on it), but just in
case...

In the Administrator:Command Prompt window, use the good ol' DOS command Dir
with a couple of switches.  (As always in a "DOS" window, enter the command
followed by /? to see a mini-help file of the switches and parameters
available with it:  dir /?  )

To start at the top:
Dir C:\ /s /a

Now go get a cup of coffee while thousands (yep!) of filenames/foldernames
scroll up your screen!  (Ctrl+C will interrupt the listing if you don't have
time for coffee just now.)

The C:\ makes the Directory listing start in the Root (\) of Drive C:.
Since no filename is specified, it will list all files in that folder except
those with Attributes set (such as Hidden or System).  The /a shows All
files, even the ones with those Attributes.  And the /s includes files in
all subfolders under the starting folder - the whole tree.  If a file is in
Drive C:, this command will show it, no matter which folder it is in and no
matter whether it is hidden!

That display actually isn't much use except that when it finally does get to
the end, it will tell you - to the byte! - how much all your files add up
to.  That doesn't say how much "space on disk" is used, because it will only
show 1 byte for a 1-byte file, but the file probably uses a whole 4 KB
cluster.  And every file has, on average, 1/2 cluster (2 KB) of wasted
space.  So 1,000 random-sized files will probably waste 2 MB of space.  A
disk full of a few big files doesn't waste much, but one with millions of
small files will waste a lot!

Now, try this again, but this time:
Dir C:\ /s /a /p

This will do the same as before, but the /p will make it pause after each
page.  For a long listing, this gets mighty tedious, but it comes in handy
to see subtotals by folder and to zero in on likely suspects.  If you find
that the C:\Whopper folder has over 10 GB of files in it, you can try
simply:
C:\Whopper

If that doesn’t show all those files, then use one or more of the other
switches:
C:\Whopper /a
C:\Whopper /s /p

I'm sure you can figure out the rest of this.  ;^}

Please post back with what you find out.  That feedback should help us help
the next person with a similar question.

RC